Molten metal reactor utilizing molten metal flow for feed material and reaction product entrapment

ABSTRACT

A molten metal reactor ( 10 ) quickly entrains a feed material in the molten reactant metal ( 16 ) and provides the necessary contact between the molten reactant metal and the feed material to effect the desired chemical reduction of the feed material. The reactor ( 10 ) includes a unique feed structure ( 24 ) adapted to quickly entrain the feed material into the molten reactant metal ( 16 ) and then transfer the molten reactant metal, feed material, and initial reaction products into a treatment chamber ( 12 ). A majority of the desired reactions occur in the treatment chamber ( 12 ). Reaction products and unspent reactant metal are directed from the treatment chamber ( 12 ) to an output chamber ( 14 ) where reaction products are removed from the reactor. Unspent reactant metal ( 16 ) is then transferred to a heating chamber ( 15 ) where it is reheated for recycling through the system.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is related to U.S. Provisional PatentApplication Serial No. 60/271,825 filed Feb. 27, 2001 and entitled“MOLTEN METAL REACTOR UTILIZING MOLTEN METAL FLOW FOR FEED MATERIAL ANDREACTION PRODUCT ENTRAPMENT.” The Applicant claims the benefit of thisearlier provisional application pursuant to 35 U.S.C. §119(e). Theentire content of this earlier provisional application is herebyincorporated herein by this reference.

TECHNICAL FIELD OF THE INVENTION

[0002] This invention relates to molten metal reactors for treatingwaste materials and soils contaminated with waste materials. Moreparticularly, the invention relates to a molten metal reactor having animproved arrangement for entraining or entrapping feed materials with amolten reactant metal to effect the desired chemical reduction of thefeed material. The invention encompasses a molten metal reactorapparatus, a structure for introducing a feed material into such areactor, a method for treating waste material with a molten metal, and amethod for introducing a feed material into a molten metal reactor.

BACKGROUND OF THE INVENTION

[0003] Molten metal reactors utilize a molten reactant metal tochemically react with a feed material in order to reduce the feedmaterial to relatively innocuous compounds and chemical elements. Forexample, U.S. Pat. No. 5,000,101 to Wagner discloses a molten metalreactor for treating chlorinated hydrocarbons and other dangerousorganic chemicals to produce carbon, metal salts, and gases such asnitrogen and hydrogen. U.S. Pat. No. 5,271,341 to Wagner discloses amolten metal reactor for treating boxed biomedical wastes which mayinclude hazardous biological wastes mixed with other materials andmetals. The disclosed molten reactant metal chemically reducesbiological materials and other organic materials in this waste tocarbon, metal salts and elemental gasses. Metals such as stainless steel“sharps” in the waste dissolve or melt into the reactant metal.

[0004] A consistent issue with molten metal reactors is providing thenecessary contact between the material to be treated or reacted, thatis, the “feed material,” and the molten reactant metal. U.S. Pat. No.5,271,341 to Wagner discloses submerging the boxed biomedical wastes inthe reactant metal bath with a submerging or plunger structure toprovide the desired contact between the waste material and the moltenreactant metal. Although the submerging structure works well withcertain types of waste materials, such structures are not well suitedfor submerging other types of materials. In particular, plungerstructures are not well suited for use in relatively high-volume wastetreatment applications in which relatively large quantities of loose orbulk feed materials, such as contaminated soils, for example, must beprocessed.

SUMMARY OF THE INVENTION

[0005] A molten metal reactor according to the present invention quicklyentrains a feed material in the molten reactant metal and provides thenecessary contact between the molten reactant metal and the feedmaterial to effect the desired chemical reduction of the feed material.The quick entrainment of feed material in the molten reactant metal isaccomplished with a unique feed structure in which the feed material isadded to the reactant metal and then quickly transferred into atreatment chamber together with the molten reactant metal and anyinitial reaction products. A majority of the desired reactions occur inthe treatment chamber. Reaction products and unspent reactant metal arepreferably directed from the treatment chamber to an output chamberwhere reaction products are removed from the reactor. Unspent reactantmetal is then preferably transferred to a heating chamber where it isreheated for recycling through the system.

[0006] According to the invention, the feed structure associated withthe reactor introduces feed material into the molten reactant metal sothat a flow of molten reactant metal immediately carries substantiallyall of the feed material and any initial reaction products into thetreatment chamber. The feed material and reaction products are thentrapped in the treatment chamber preferably by means of a suitablegravity trap structure. This combination of substantially immediateintroduction into the treatment chamber and trapping in the treatmentchamber helps ensure that the feed material and any intermediatereaction products have sufficient contact with the molten reactant metalto provide the desired chemical reactions, that is, the substantiallycomplete chemical reduction of the feed material.

[0007] The desired contact with the reactant metal is enhanced accordingto the invention by inducing a swirling or vortex flow in the moltenreactant metal in a feed chamber in which the feed material first makescontact with the molten reactant metal. This swirling flow may beproduced in any suitable fashion, including by directing the moltenmetal into the feed chamber in an off center position, by driving themolten metal in the feed chamber with an impeller, or both. Also, abowl-shaped feed chamber helps facilitate the desired swirling flow.

[0008] In order to carry the feed material and any initial reactionproducts quickly into the treatment chamber in the flow of moltenreactant metal, the feed material preferably comes into contact with themolten reactant metal in an area adjacent to an inlet to the treatmentchamber. An area “adjacent” to the treatment chamber inlet means thearea of the surface of the molten reactant metal in the feed chambergenerally nearest to the inlet of the treatment chamber. In the form ofthe invention in which a swirling flow is induced in the feed chamber,the feed material drops into the molten reactant metal in a central areaof the feed chamber, at the center of the swirling flow or vortex, anddirectly above an outlet from the feed chamber/inlet to the treatmentchamber. The feed chamber includes an outlet that at least borders thetreatment chamber inlet and more preferably comprises a common openingwith the treatment chamber inlet. By “bordering” the treatment chamberinlet it is meant that the feed chamber outlet is in the immediatevicinity of the treatment chamber inlet so that there is only a smalldistance between any point of the feed chamber outlet and any point ofthe treatment chamber inlet.

[0009] The feed material may include substantially any material ormixture of materials suitable for treatment in a molten metal reactor.These materials include hydrocarbons and halogenated hydrocarbons, lowand high level radioactive materials, and any other materials that maybe chemically reduced in a molten reactant metal such as aluminum,magnesium, or combinations of these metals together with other metals.The invention is particularly suited to treating soils and other bulksolids which have been contaminated with hydrocarbons, halogenatedhydrocarbons, other chemically reducible materials, radioactivematerials, and metals. As used in this disclosure and the accompanyingclaims a “feed material” may comprise any of the above-describedmaterials or combinations of these materials.

[0010] It will be appreciated by those skilled in the art of moltenreactors that the chemical reduction reactions produced by contact witha molten reactant metal may not immediately reduce a given constituentcompound included in a feed material. Rather, many chemical compoundssuitable for treatment with a molten reactant metal may initially reactin or with the metal to produce intermediate reaction products. Theseintermediate reaction products are then further reduced by reaction inor with the molten reactant metal. The reactions continue in the moltenreactant metal until the reduction reactions are substantially complete,leaving only final reaction products. Metals in the feed materialcompounds are generally reduced to their elemental state, carbon isreduced to its elemental state and goes to a gaseous state at thetemperature of the molten reactant metal, halogens form salts witheither metals from the molten reactant metal bath or with metalscontained in the feed material itself. Nitrogen and hydrogen liberatedfrom the reacted compounds escape from the molten metal bath as gases.Minerals included in soil generally remain unreacted in the moltenreactant metal depending upon the makeup of the molten reactant metalbath and its temperature, but may go to a liquid state at thetemperature of the molten metal bath.

[0011] As used in this disclosure and the accompanying claims, the term“reaction product” is used to refer to any reaction product produced bytreatment of the feed material with the molten reactant metal, whetherthe reaction product is an initial reaction product subject to furtherreactions in the molten metal or a final reaction product that ischemically stable in the molten reactant metal. The term “reactionproduct” also refers to materials such as quartz that do not chemicallyreact with the molten reactant metal but may be contained in soilcontaminated with materials that do react in the molten reactant metal.Thus, the term “reaction product” means generally any material thatresults from any reaction of a feed material occurring in the moltenreactant metal.

[0012] The above-described advantages and features of the invention,along with other advantages and features, will be apparent from thefollowing description of the preferred embodiments, considered alongwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is a diagrammatic view in section showing a molten metalreactor embodying the principles of the invention.

[0014]FIG. 2 is a diagrammatic top plan view of the molten metal reactorshown in FIG. 1.

[0015]FIG. 3 is a diagrammatic view in section similar to FIG. 1 butshowing an alternate form of the feed arrangement.

[0016]FIG. 4 is a diagrammatic view in section similar to FIG. 3,showing yet another alternate feed arrangement according to theinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Referring particularly to FIGS. 1 and 2, a molten metal reactor10 embodying the principles of the invention includes essentially fourchambers including a bowl-shaped vortex or feed chamber 11, a treatmentchamber 12, an output chamber 14, and a heating chamber 15. Each ofthese chambers is adapted to contain a molten reactant metal indicatedby the reference numeral 16. The level of molten reactant metal 16 infeed chamber 11, output chamber 14 and heating chamber 15 is indicatedby the dashed line in the respective chamber. Molten reactant metal 16is heated to the desired temperature in heating chamber 15 and thentransferred to feed chamber 11. From feed chamber 11, molten reactantmetal 16 flows rapidly into treatment chamber 12 and then exits thetreatment chamber into output chamber 14. From output chamber 14, moltenreactant metal 16 returns to heating chamber 15 for reheating andrecycling through the reactor 10. Reaction products are removed fromreactor 10 through output chamber 14. According to the invention, theflow of molten reactant metal from feed chamber 11 to treatment chamber12 carries feed materials to be treated into the treatment chamber alongwith substantially all reaction products liberated from the feedmaterial on initial contact with the molten reactant metal. Treatmentchamber 12 provides sufficient residence time to completely reactsubstantially all constituents in the feed material.

[0018]FIG. 1 in particular indicates that molten metal reactor 10includes numerous components that contain or come in contact with moltenreactant metal 16. All components that do come in contact with themolten reactant metal are either formed from a material which isresistant to damage from the reactant metal or coated with such aprotective material. For example, the system of chambers 11, 12, 14, and15 may be cast from a refractory material or may be formed from a basematerial which is then coated with a suitable refractory or otherchemically resistant material.

[0019] The particular reactant metal utilized in reactor 10 will dependupon the constituents in the feed material which must be destroyed orremoved from non-hazardous constituents of the feed material. Apreferred reactant metal suitable for use in treating many types ofchemicals comprises an alloy of aluminum as disclosed in U.S. Pat. No.5,000,101 to Wagner, the entire content of which is hereby incorporatedin this disclosure. However, it will be appreciated that the makeup ofreactant metal 16 may be varied to suit a particular feed material to betreated in reactor 10 and is not limited to aluminum or aluminum alloys.Also, the temperature of reactant metal 16 may be varied to suit theparticular feed material to be treated.

[0020] Reactor 10 is well suited for treating a number of feedmaterials, including particularly contaminated soils. The soils may becontaminated with halogenated hydrocarbons or other organic compounds,metals, and low-level radioactive materials. Organic compounds arereduced to liberate carbon and hydrogen. Halogens included in organiccompounds generally react with elements of the reactant metal to formmetal salts, while other materials dissolve or melt into the moltenreactant metal or release from the reactant metal as a gas. Manyradioactive materials dissolve or melt into the reactant metal 16 wherethe radioactive isotopes can be concentrated to the desired leveltogether with radioactive emission absorbing elements. Molten reactantmetal and absorbing metal containing the radioactive isotopes may thenbe drawn off to form ingots that can safely store the radioactiveisotopes.

[0021] In addition to the chamber arrangement shown in FIGS. 1 and 2,the preferred reactor 10 includes molten metal pumps 20 and 21 shown inFIG. 2, and a heater arrangement 22 associated with at least heatingchamber 15. A feed arrangement 24 is associated with feed chamber 11 fortransferring feed materials into the system. Also, the illustratedreactor 10 includes a reaction product removal arrangement associatedwith output chamber 14. The reaction product removal arrangement isshown generally at reference numeral 25.

[0022] Referring to both FIGS. 1 and 2, feed chamber 11 includes anoutlet 28 generally at the bottom of the feed chamber. Feed arrangement24 is located preferably immediately over or above outlet 28. Moltenreactant metal 16 is supplied into feed chamber 11 through an inlet 29.As shown best in FIG. 2, the preferred form of the invention has inlet29 positioned off-center from a center vertical axis of feed chamber 11so that the flow of reactant material into the chamber helps induce aswirling or vortex flow in the feed chamber as will be described furtherbelow. Referring still to FIG. 2, reactant metal 16 collects in a supplychamber 31 prior to flowing into feed chamber 11. This flow may becontinuous or may be on a batch basis. Where reactant metal is releasedinto feed chamber 11 in batches, a suitable valve (not shown) may beassociated with inlet 29. The valve may be closed to allow reactantmetal 16 to collect in supply chamber 31 then may be opened to suddenlyrelease the reactant metal into feed chamber 11.

[0023] It will be appreciated that it is possible to eliminate pump 21and instead use a moveable crucible or vessel to periodically liftmolten reactant metal from heating chamber 15 and pour the molten metalinto supply chamber 31. This moveable crucible form of the invention maybe used to introduce a rapid flow of molten reactant metal into supplychamber and then into feed chamber 11.

[0024] The preferred form of the invention produces a vortex or swirlingflow in the reactant metal 16 contained in feed chamber 11 as the moltenmetal flows rapidly into the feed chamber and then into treatmentchamber 12. In the form of the invention shown in FIGS. 1 and 2, theoff-center molten metal inlet 29, bowl-shaped feed chamber 11, and flowrate of molten reactant metal all combine to provide a vortex inducingarrangement. The swirling flow of reactant metal 16 in feed chamber 11provides a good mixing action to rapidly incorporate or ingest the feedmaterial into the reactant metal. It will be appreciated that theswirling reactant metal or vortex flow of molten reactant metal in feedchamber 11, is not necessary to the present invention but is helpful tothe operation of the present invention. Sufficient reactant metal 16flow rates may be produced to provide the desired waste materialentrainment without inducing a vortex in the reactant metal as it flowsfrom feed chamber 11 into treatment chamber 12. For example, moltenmetal pump 21 may pump molten reactant metal into feed chamber 11 at arate on the order of fifteen thousand (15,000) pounds per minute toproduce high molten metal flow velocities from an appropriately sizedfeed chamber outlet to an appropriately sized treatment chamber inlet.

[0025] Feed arrangement 24 is adapted to transfer feed materials intoreactor 10 while minimizing the amount of oxygen entering the reactor.Feed arrangement 24 includes an elongated chute 35 which is preferablycentered within feed chamber 11 to drop feed material into the center ofvortex 32, immediately above or adjacent to outlet 28 from the feedchamber to treatment chamber 12. The bottom end of feed chute 35 may bereferred to as a feed material inlet into feed chamber 11. Feed chute 35includes a purge chamber 36 defined between an upper dump gate 38 and alower dump gate 39. A purge gas, in this case flue gas from heaterarrangement 22 is circulated to the purge chamber through conduit 40 topurge chamber 36 of oxygen. In operation, lower dump gate 39 is held ina closed position sealing a bottom of purge chamber 36 while upper dumpgate 38 is held open and feed material is loaded into the purge chamber.Once purge chamber 36 is loaded with feed material, upper dump gate 38is closed and purge gas is circulated through the chamber to purge thechamber of oxygen. After the chamber is sufficiently purged, lower dumpgate 39 is opened so that the feed material in chamber 36 drops into themolten reactant metal in feed chamber 11. The opening of lower dump gate38 to drop feed material into feed chamber 11 may be coordinated withthe release of molten reactant metal 16 into the feed chamber to createthe desired swirling flow and suction effect as the molten reactantmetal flows out of the feed chamber and into treatment chamber 12.

[0026] An additional sealing conduit 42 may be associated with the feedchute 35 to isolate the area of feed chamber 11 generally above oradjacent to the feed chamber outlet 28. Additional sealing conduit 42may be used to ensure that the feed material and reaction products flowalong with the reactant metal 16 into treatment chamber 12. It will alsobe noted that the top of feed chamber 11 above the level of reactantmetal 16 is sealed to the atmosphere so that any reaction products thatmay remain in feed chamber 11 are not released to the atmosphere.

[0027] Treatment chamber 12 comprises a tube or conduit extending fromthe feed chamber outlet opening 28 to output chamber 14. The preferredtreatment chamber 12 also includes a gravity trap 44 having a U-shapedsegment that helps prevent gases from flowing back into feed chamber 11.Treatment chamber 12 is long enough to provide sufficient residencetime, considering the reactant metal flow rate through the tube, toeffect a substantially complete reaction of materials that are to bedestroyed in the molten metal reactor. Residence times should beapproximately three (3) minutes to effect the desired treatment for mostfeed materials. The flow velocity in treatment chamber 12 may be eight(8) feet per minute.

[0028] In order to help maintain the reactant metal 16 at a desiredtreatment temperature in treatment chamber 12, the treatment chamber maybe located immediately adjacent to heating chamber 15 so that heat fromthe heating chamber is transferred to material within the treatmentchamber. Also, although not shown in the drawing, a separate heatingsystem may be associated with the treatment chamber 12 for maintainingthe temperature of the molten metal at a desired temperature within thetreatment chamber. Any suitable heating system may be used withtreatment chamber 12 including an induction heating system using one ormore electromagnetic field induction coils positioned adjacent to thetreatment chamber.

[0029] Although a molten reactant metal level is shown by a dashed linein FIG. 1 for chambers 11, 14 and 15, FIG. 1 does not show a moltenreactant metal level in treatment chamber 11. This should not be takento imply that there will be no gas phase in treatment chamber 12. Formany feed materials, a distinct gas phase of reaction products willemerge in the top of treatment chamber 12. However, these reactionproducts will be held in close proximity to the surface of the moltenreactant metal 16 in position to facilitate further reaction of thereaction product if not fully reduced. Gaseous reaction products willalso bubble up through molten reactant metal in the output chamber 14 toallow any further reactions possible between the reaction products andmolten reactant metal.

[0030] A molten metal reactor within the scope of the present inventionmay include a feed chamber having an outlet that is separate anddistinct from an inlet to the treatment chamber in the reactor. However,in the preferred form of the invention shown in FIGS. 1 and 2, feedchamber outlet 28 is common with the inlet to treatment chamber 12, thatis, the feed chamber outlet and treatment chamber inlet comprise thesame opening. The outlet from the feed chamber according to theinvention at least borders the inlet to the treatment chamber. Thisproximity between feed chamber outlet 28 and the inlet to the treatmentchamber combined with the proximity between the point at which the feedmaterial makes initial contact with the molten reactant metal 16 and therapid flow of molten reactant metal into treatment chamber 12 ensuresthat the feed material and even any initial reaction products arecarried into the treatment chamber where the desired reactions mayproceed to completion. The residence time for feed materials in the feedchamber after initial contact with the molten reactant metal should beon the order of ten (10) seconds or less. Residence times in this rangewill be considered insignificant residence times within the scope of thefollowing claims.

[0031] Output chamber 14 is connected to receive material exiting anoutlet 45 of treatment chamber 12. The material which flows into outletchamber 14 includes molten reactant metal 16 remaining after the desiredreactions with the feed material and reaction products from the reactionof the feed material with the reactant metal. The reaction products mayinclude molten or gaseous metal salts, gaseous carbon, unreacted solidssuch as clay particles included in the feed material, metals from thefeed material that have dissolved or melted into the reactant metal, andother gases liberated in the various reactions between the moltenreactant metal 16 and the feed material. These other gasses willcommonly include primarily nitrogen and hydrogen.

[0032] The reaction product removal arrangement 25 associated withoutput chamber 14 includes a skimming system shown generally atreference numeral 49 and a gas and particulate removal system showngenerally at reference numeral 50. A tapping system including tappingline 51 with a suitable valve may also be connected to output chamber 14for removing heavy molten material or dissolved material that maysegregate to the bottom of the output chamber.

[0033] Gas and particulate removal system 50 includes a collection hood54 at the top of output chamber 14 and an outlet conduit 55. This outletconduit 55 preferably leads to particulate control equipment (PCE) 56such as a bag house or an aqueous scrubber that removes particulatesincluded in, or forming from, the gases exiting output chamber 14through conduit 55. Flue gas from the heater arrangement 22 may bedirected into collection hood 54 through conduit 57 to enhance the flowof gases and particulates out of the system through conduit 55. Thepurge gas from purge chamber 36 may also be directed into conduit 55 toexit the system through particulate control equipment 56.

[0034] Skimming system 49 is located at the top of output chamber 14 forremoving solids and light molten materials that segregate to the top ofthe reactant metal 16 in the output chamber. The illustrated skimmingsystem 49 includes an auger 58 which is rotated by a suitable drivedevice 59 to skim material floating at the surface of the moltenreactant metal 16 to the right in FIG. 1 toward an outlet chute 60.Outlet chute 60 leads to an airlock chamber 61 defined between an upperairlock gate 62 and a lower air lock gate 63. In operation, lower gate63 is closed and upper gate is held open while auger 59 skims materialthrough outlet chute 60 and into the airlock chamber 61 above the lowergate. After an appropriate amount of skimmed material has collected inairlock chamber 61, upper gate 62 is closed and lower gate 63 is openedto allow material collected in the air lock chamber to drop into acollection vessel 64. Positive pressure maintained in the collectionhood 54 provided by the heater flue gas helps ensure significant amountsof oxygen does not flow into the reactor 10 as solid material and lightmolten material is removed through airlock chamber 61.

[0035] One or more deflectors such as deflector 66 may be associatedwith output chamber 14 to deflect reaction products to the desiredlocations within the outlet chamber and ensure that materials do notinadvertently enter heating chamber 15. Deflectors may also be used inoutlet chamber to enhance contact with the molten reactant metal andhelp ensure that the desired reactions proceed to completion. That is,deflectors in output chamber 14 may be arranged to cause relativelylight reaction products to follow a tortuous path through the moltenreactant metal in output chamber 14 before reaching the surface of themolten reactant metal.

[0036] Heating chamber 15 comprises a chamber having a lower portionadapted to contain a volume of reactant metal and an upper area which isisolated from the feed chamber 11 and output chamber 14. This isolationis required in the illustrated form of the invention to accommodate thegas fired burners 70 that make up heating arrangement 22 used to heatthe reactant metal 16 within heating chamber 15. Exhaust gas fromburners 70 exits the upper part of the heating chamber through flue gasstack 71. A portion of this flue gas is directed to purge chamber 36 andto collection hood 54 as described above. Although gas fired burners areshown in the illustrated form of the invention, other heating systemssuch as an induction heating system for example, may be employed to heatthe reactant metal 16 in heating chamber 15. Of course, whenelectromagnetic induction heating is used to heat reactant metal 16, aseparate purge gas must be used in connection with feed purge chamber 36and collection hood 54 since the flue gas would not be present.

[0037] Proper flow and circulation of molten reactant metal 16 inreactor 10 is important to the proper operation of the reactor. Inparticular, the flow of molten reactant metal 16 from feed chamber 11 totreatment chamber 12 should be at a sufficient rate to entrain or entrapfeed material and substantially any initial reaction products, and causethese materials to be carried or swept into the treatment chamber andultimately into output chamber 14. Minimum flow velocities of moltenreactant metal into treatment chamber 14 will depend upon the fluidproperties of the particular molten reactant metal and the specificgravity and other properties of the feed material. The desired flowrates may be produced using pumps for moving the molten reactant metal.FIG. 2 shows two molten metal pumps in the preferred form of theinvention. Pump 20 pumps molten reactant metal 16 from output chamber 14to heating chamber 15. Pump 21 pumps the heated or reheated moltenreactant metal 16 from heating chamber 15 to feed chamber 11, in theillustrated case through supply chamber 31.

[0038] It will be noted from FIG. 1 that the level of molten reactantmetal 16 in feed chamber 11 may be higher than in heating chamber 15 andoutput chamber 14. In this arrangement the molten reactant metal 16provides a hydrostatic head which helps cause the molten metal to flowfrom feed chamber 11 into treatment chamber 12 and then into outputchamber 14. However, the desired flow rates and vortex or swirling flowmay be produced without the higher molten reactant metal level in feedchamber 11. Also, it will be appreciated that the desired flow rates ofmolten reactant metal into treatment chamber 14 may be produced withoutthe illustrated molten metal pumps. As discussed above, in alternativearrangements a portion of the molten reactant metal from heating chamber15 may be lifted in a suitable vessel and dumped into feed chamber 11(or into supply chamber 31) in order to produce the desired flow ofreactant metal 16 through the feed chamber and into treatment chamber12. Alternatively, molten reactant metal 16 may be collected in supplychamber 31 and in released abruptly to flush feed material from feedchamber 11 into treatment chamber 12.

[0039]FIG. 3 shows an alternate vortex inducing arrangement according tothe invention. This alternative form of the invention includes the samepreferably bowl-shaped feed chamber 11, treatment chamber 12, andheating chamber 15 included in the embodiment shown in FIGS. 1 and 2.FIG. 3 is broken to omit other portions of the reactor that areidentical to those set out in FIGS. 1 and 2, and do not involve thealternate vortex inducing arrangement. In the form of the inventionshown in FIG. 3, an impeller 80 is included to help induce the desiredswirling or vortex flow of molten reactant metal in feed chamber 11.Impeller 80 may comprise any suitable impeller device suitable for usein a molten reactant metal. U.S. Pat. No. 4,930,986 shows a suitableimpeller, and is incorporated herein by this reference. The type ofimpeller shown in this patent also forces feed material and moltenreactant metal downwardly in feed chamber 11 toward the outlet totreatment chamber 12. Impeller 80 is driven by drive shaft 81 about avertical axis V aligned generally in the center of feed chamber 11. Asuitable motor and drive device 82 rotates drive shaft 81. Drive shaft81 preferably extends though a protective conduit 84. Conduit 84 helpsprotect drive shaft 81 from feed material entering the reactor throughfeed arrangement 85.

[0040] Because the center portion of feed chamber 11 is occupied by theimpeller 80 and supporting structure, feed arrangement 85 differs fromfeed arrangement 24 shown in FIG. 1. Feed arrangement 85 includes anelongated feed chute 86 that extends at an acute angle with respect toaxis V. Feed chute 86 includes upper and lower dump gates 87 and 88respectively to define a purge chamber 89 similar to purge chamber 36shown in FIG. 1. The dump gates purge line 90 and purge chamber alloperate similarly to the corresponding elements shown in FIG. 1 and thuswill not be described further here.

[0041] An outlet end 91 of feed chute 86 represents a feed materialinlet to feed chamber 11 and terminates in a sealing or confinementconduit 94 similar to the sealing conduit 42 shown in FIG. 1 andfunctions similarly to help confine feed material just to the volume ofmolten reactant metal 16 immediately above the feed chamber outlet 28.

[0042] The flow rate of molten reactant metal 16 into and out of feedchamber 11 may be the same as in the embodiment described with referenceto FIGS. 1 and 2. Thus, the flow of molten metal 16 through inlet 29 andthe bowl shape of feed chamber 11 may be sufficient to induce someswirling flow in the feed chamber around axis V. Impeller 80 enhancesthe swirling flow and further helps to submerge and entrain feedmaterial in the molten reactant metal 16 so that the feed material maybe quickly carried in the flow of molten metal into treatment chamber12.

[0043]FIG. 4 shows yet another alternate feed arrangement for a reactorwithin the scope of the present invention. This alternative feedarrangement includes a treatment chamber 12 and heating chamber 15similar to those described in FIG. 1. The output chamber 14 and relatedcomponents are also similar to those shown in FIG. 1 and are thereforeomitted from FIG. 4.

[0044] The alternative feed arrangement shown in FIG. 4 includes a feedchamber 95 that is just large enough in diameter to accommodate animpeller 96 similar to impeller 80 described above with reference toFIG. 3. Impeller 96 is driven on a shaft 97 by motor 98 and the shaft isprotected by housing 99. Molten reactant metal 16 enters feed chamber 95through inlet 101 which preferably resides near the level of moltenreactant metal maintained in the feed chamber. Impeller 96 is positionedso that it traverses the level of the molten reactant metal 16 in feedchamber 95, and preferably comprises an impeller such as that describedin U.S. Pat. No. 4,930,986 to force materials downwardly along axis V inthe feed chamber. The illustrated preferred positioning of impeller 96also allows the impeller to contact and quickly submerge feed materialsinto the molten reactant metal 16 in feed chamber 95. In otherarrangements within the scope of the accompanying claims, the impellermay be located below the level of molten reactant metal in feed chamber95. In other arrangements within the scope of the invention or set outin the accompanying claim, the impeller may be below the level of moltenreactant metal.

[0045] Feed materials enter feed chamber 95 through feed materialconduit 104. A suitable feed material pump 105 pumps or forces feedmaterial from a feed material supply vessel 106 through conduit 104 andinto feed chamber 95. Feed material pump 105 may comprise a diaphragmpump or an auger type pump for example. This feed material arrangementshown in FIG. 4 is particularly suited for feed materials in the form ofloose particles such as loose soils or feed materials in the form of aslurry.

[0046] The pumping arrangement for the feed material obviates the needfor the purge chamber and dump gate arrangement shown in FIGS. 1 and 3.The positive pressure provided by pump 105 prevents gasses from exitingfeed chamber 95 through feed material conduit 104. A pressure reliefline 107 with suitable valving may be provided in the top of feedchamber 95 to periodically remove reaction product gasses or othergasses that might collect in the feed chamber. Depending upon the natureof these gasses, the gasses removed through line 107 may or may not besubjected to treatment before release to the atmosphere. In some casesthe gasses may simply be directed through particulate control equipmentassociated with the reactor's reaction product removal equipment shownin FIG. 1.

[0047] The above described preferred embodiments are intended toillustrate the principles of the invention, but not to limit the scopeof the invention. Various other embodiments and modifications to thesepreferred embodiments may be made by those skilled in the art withoutdeparting from the scope of the following claims. For example, the feedpump and feed conduit 104 arrangement shown in FIG. 4 may be replaced bythe feed chute and dump gate arrangement shown in FIG. 3, and the feedchambers 11 shown in FIGS. 1 and 3 may include a relief line similar toline 107 shown in FIG. 4. Also, those skilled in the art will appreciatethat many technical details have been omitted from the diagrammaticrepresentations shown in FIGS. 1 and 2 in order to avoid obscuring theinvention in unnecessary detail. These details such as valves andcontrol systems will be apparent to those of ordinary skill in the artfrom the above description of molten metal reactor 10.

1. A method of operating a molten metal reactor to treat a feedmaterial, the method including the steps of: (a) inducing a flow ofmolten reactant metal from a feed chamber through a feed chamber outletto a treatment chamber; (b) introducing the feed material into themolten reactant metal at a location adjacent to the feed chamber outlet;and (c) wherein the flow of molten reactant metal from the feed chamberto the treatment chamber is at a rate sufficient to carry reactionproducts and feed material from the feed chamber into the treatmentchamber without significant residence time in the feed chamber.
 2. Themethod of claim 1 wherein the step of introducing the feed material intothe molten reactant metal is performed at a location immediately abovethe feed chamber outlet.
 3. The method of claim 2 further including thestep of containing the feed material in an area immediately above thefeed chamber outlet as the feed material falls into the molten reactantmetal in the feed chamber.
 4. The method of claim 1 further includingthe step of inducing a swirling flow of molten reactant metal in thefeed chamber.
 5. The method of claim 4 further including the step ofintroducing the molten reactant metal into the feed chamber at an offsetposition to induce the swirling flow in the feed chamber.
 6. The methodof claim 1 further including the step of directing the molten reactantmetal through a gravity trap associated with the treatment chamber. 7.The method of claim 1 further including the step of adding heat to thematerials in the treatment chamber.
 8. The method of claim 7 wherein thestep of adding heat to the materials in the treatment chamber isperformed by a heating device associated with the treatment chamber. 9.The method of claim 7 wherein the step of adding heat to the materialsin the treatment chamber is performed by heat transfer with moltenreactant metal contained in an additional chamber.
 10. The method ofclaim 1 further including the step of directing molten reactant metaland reaction products from the treatment chamber to an output chambercontaining a supply of molten reactant metal, wherein the moltenreactant metal and reaction products are directed into the outletchamber at a level below the level of molten reactant metal contained inthe output chamber.
 11. The method of claim 10 further including thesteps of: (a) removing reaction products from the output chamber; (b)transferring the molten reactant metal from the output chamber to aheating chamber; and (c) adding heat to the molten reactant metal in theheating chamber.
 12. A method of introducing a feed material into amolten reactant metal, the method including the steps of: (a) carryingthe feed material and reaction products into a treatment chamber withina flow of molten reactant metal; and (b) trapping the feed material andthe reaction products in the treatment chamber together with the moltenreactant metal.
 13. The method of claim 12 further including the step ofcausing the feed material to come into contact with the molten reactantmetal in an area adjacent to an inlet to the treatment chamber.
 14. Themethod of claim 13 further including a feed chamber connected to theinlet to the treatment chamber and including the step of introducing thefeed material to the molten reactant metal in the feed chamber.
 15. Themethod of claim 14 wherein the inlet to the treatment chamber is at abottom of the feed chamber and including the step of inducing a swirlingflow in the feed chamber.
 16. The method of claim 12 wherein the step oftrapping the reaction products and feed material in the treatmentchamber includes causing the molten reactant metal to flow through agravity trap in the treatment chamber.
 17. The method of claim 12further including the step of adding heat to the molten reactant metalas it flows through the treatment chamber.
 18. A molten metal reactorincluding: (a) a treatment chamber having a treatment chamber inlet; (b)a molten reactant metal flow inducing arrangement for inducing a flow ofmolten reactant metal into the treatment chamber through the treatmentchamber inlet; (c) a feed chamber having a feed chamber outlet locatedadjacent to the treatment chamber inlet; (d) an output chamber connectedto an outlet of the treatment chamber to receive molten reactant metaland reaction products from the treatment chamber; and (e) a supplychamber connected to the output chamber and to the treatment chamber.19. The molten metal reactor of claim 18 wherein the feed chamber outletand the treatment chamber inlet comprise a common opening.
 20. Themolten metal reactor of claim 19 further including a vortex inducingarrangement for inducing a swirling flow in the feed chamber outlet. 21.The molten metal reactor of claim 19 wherein the feed chamber comprisesa bowl shaped chamber and the feed chamber outlet is located insubstantially the center of the bowl shape at a bottom of the feedchamber.
 22. The molten metal reactor of claim 19 further including animpeller mounted in the feed chamber and adapted to be rotated about asubstantially vertical axis.
 23. The molten metal reactor of claim 19including an off-center molten reactant metal inlet to the feed chamberthrough which molten reactant metal is introduced into the feed chamberto induce a swirling flow in the feed chamber.
 24. The molten metalreactor of claim 18 wherein at least a portion of the treatment chamberis in a heat transfer relationship with the supply chamber.
 25. Themolten metal reactor of claim 18 further including a gravity trap withinthe treatment chamber.
 26. A feed structure for introducing a feedmaterial into a treatment chamber of a molten metal reactor, the feedarrangement including: (a) a feed chamber having a feed chamber outletlocated adjacent to an inlet to the treatment chamber; (b) a feedmaterial inlet to the feed chamber, the feed material inlet beingsubstantially aligned with the feed chamber outlet; and (c) a moltenreactant metal flow inducing arrangement for inducing a flow of moltenreactant metal into the treatment chamber through the treatment chamberinlet and through the length of the treatment chamber to a treatmentchamber outlet, the flow of molten reactant metal being at a ratesufficient to carry feed material and reaction products into thetreatment chamber.
 27. The feed structure of claim 26 wherein the feedchamber outlet and the treatment chamber inlet comprise a commonopening.
 28. The feed structure of claim 27 wherein the feed materialinlet is located in a central portion of the feed chamber.
 29. The feedstructure of claim 28 further including a containment conduit extendingfrom the feed material inlet to a level below the level of moltenreactant metal in the feed chamber in an area below the feed materialinlet.
 30. The feed structure of claim 27 further including vortexinducing arrangement for inducing a swirling flow in the feed chamber,the flow having an axis substantially aligned with an axis of the feedchamber outlet.
 31. The feed structure of claim 27 wherein the feedchamber comprises a bowl shaped chamber and the feed chamber outlet islocated in substantially the center of the bowl shape at a bottom of thefeed chamber.
 32. The feed structure of claim 27 further including animpeller mounted in the feed chamber and adapted to be rotated about asubstantially vertical axis.
 33. The feed structure of claim 27including an off-center molten reactant metal inlet to the feed chamberthrough which molten reactant metal is introduced into the feed chamberto induce a swirling flow in the feed chamber.